Air recirculation system for cleaning apparatus



HEATER I 54 5o 2s-1 4s 3 FAN I as I I0) CONDENSER Feb. 26, 1963 I B.RAND 3,078,701

AIR RECIRCULATION SYSTEM FOR CLEANING APPARATUS Filed March 7, 1961 P 6r CONDENSER FAN *1 I l I IN V EN TOR.

F] G. 2 4 v BURTON RAND M H .w

ATTORNEY 3,078,701 AIR RECIRCULATION SYSTEM FOR CLEANING APPARATUSBurton Rand, Bala-Cynwyd, Pa., assignor to Autosonics Inc.,Philadelphia, Pa., a corporation of Pennsylvania Filed Mar. 7, 1961,tier. No. 94,008

6 Claims. (Cl. 68-18) This invention relates to an air recirculationsystem for a cleaning apparatus, and more particularly, a closed airrecirculation system for a cleaning apparatus utilizing a cleaningsolvent subject to being vaporized during the cleaning action. Suchsolvents are of the type commonly used in dry cleaning apparatus,degreasing apparatus, etc. and including fluorinated hydrocarbons,chlorinated hydrocarbons, such as trichlorethylene, etc.

The present invention is not limited in its use with any particular typeof cleaning apparatus. The cleaning apparatus may be a degreasingapparatus wherein machined parts are conveyed through the apparatus bymeans of a conveyor belt, a conveyor chain, a sp-oked wheel, rotatablymounted wheels, etc. Also, the cleaning apparatus may be of the typeused for dry cleaning of wearing apparel. In cleaning apparatus for drycleaning wearing apparel, the cleaning apparel is placed within ahousing having an atmosphere laden with vaporized solvent.

It is conventional in many types of degreasing apparatus to provide achamber of solvent which is subjected to heat so as to provide a zone ofvapor above the level of liquefied solvent or rinse bath of solventwithin the cleaning apparatus. It is objectionable to have vaporizedsolvent above the vapor zone in such a degreasing apparatus.

The present invention is directed to a closed circuit air recirculationsystem for withdrawing a mixture of air and vaporized solvent fromwithin the cleaning apparatus with the air being returned to thecleaning apparatus free from vaporized solvent. In this manner, thepresent invention is capable of controlling the amount of vaporizedsolvent within the apparatus and preventing escape of the same from aninlet or outlet to the cleaning ap paratus. Accordingly, the presentinvention enables cleaning apparatus to be provided with a substantiallyopen inlet and/or outlet. That is, the inlet or outlet to the cleaningapparatus is not provided with means for closing the same such as adoor, window, etc.

The present invention enables a cleaning apparatus to be included in acontinuous cleaning system without escape of vaporized solvent to theatmosphere. Escape of vaporized solvent to the atmosphere isobjectionable because it depletes the source of liquefied solvent withinthe cleaning apparatus, the solvent is generally toxic and thereforeharmful to persons working within the area adjacent to the cleaningapparatus, and interferes with areas desired to be provided with acontrolled atmosphere.

It is an object of the present invention to provide a novel airrecirculation system for a cleaning apparatus.

It is another object of the present invention to provide a novel airclosed recirculation system Which prevents vaporized solvent fromescaping to the atmosphere surrounding the cleaning apparatus.

It is another object of the present invention to provide a novel airrecirculation system for a cleaning apparatus whereby the amount ofvaporized solvent within the cleaning apparatus may be controlled.

It is still anotherobject of the present invention to provide a novelcleaning apparatus which lacks a closure at the inlet and outletthereof, thereby enabling the cleaning apparatus to be installed in acontinuous cleaning process.

. It is still another object of the present invention to provide a novelcleaning apparatus having an air re- 3,078,701 iatented Feb. 26, 1963circulation system for controlling the amount of vaporized It is afurther object of the present invention to provide a novel cleaningapparatus with an air recirculation system wherein the movement of theair is barely perceptible.

Other objects will appear hereinafter.

For the purpose of illustrating the invention there is shown in thedrawings forms which are presently preferred; it being understood,however, that this invention is not limited to the precise arrangementsand instrumentalities shown.

FIGURE 1 is a schematic view of the present invention, partly insection.

FIGURE 2 is a schematic view of the present invention, partly insection.

Referring to the drawing in detail, wherein like numerals indicate likeelements, there is shown in FIGURE 1 a schematic view of the presentinvention, partly in section, designated generally as 10.

The cleaning apparatus 10 of the present invention includes a housing 12of a cleaning apparatus having an inlet chute 14 and an outlet chute 16.It will be appreciated that the housing 12 of the cleaning apparatus ismerely schematic and therefore representative of substantially all typesof cleaning apparatus. Since the present invention is of generalapplication to substantially all types of cleaning apparatus, the meansfor conveying the elements to be cleaned are not shown in the drawing.

Substantially any type of conventional means for conveying the elementsto be cleaned through the cleaning apparatus housing 12 may be provided.For example,

the means for causing the elements to be cleaned to move from the inlet14 to the outlet 16 may be of the type set forth in my copendingapplication Serial No. 95,183 entitled Automatic Ultrasonic CleaningDevice, filed on March 13, 1961. Alternatively, the means for moving theelements to be cleaned through the housing 12 may be of the type shownin US. Patents 1,422,309; 2,118,480;

2,714,574; and 2,802,758.

Alternatively, the means for moving the elements to be cleaned from theinlet to the outlet may be of the type set forth in my copendingapplications Serial Nos. 59,066, entitled Cleaning Apparatus, filed onSeptember 28, 1960, now Patent No. 3,019,800, and 60,106, entitledCleaning Apparatus, and filed on October 3, 1960.

For purposes of illustration, the housing 12 is provided with an uprightwall 18 which cooperates with a side Wall of the housing 12 to form achamber within which a cleaning solvent 20 is disposed. The cleaningsolvent 20 may be any one of a plurality of well known cleaning solventsincluding fluorinated hydrocarbons. It will be noted that the outlet endof the inlet chute 14 is disposed below the level of the cleaningsolvent 20 thereby illustrating one manner in which means may beprovided for preventing the escape of vaporized solvent to theatmosphere.

A conduit 22 is provided with one end of this conduit being incommunication with the. interior of the housing 12. For purposes ofillustrating, the conduit 22 extends through'a side wall of the housing12. The other end of the conduit 22 is connected to a condenser 24 shownschematically in FIGURE 1. Any one of a plurality of commerciallyavailable condensers may be utilized. Accordingly, it is not deemednecessary for the purposes of the present invention to explain in detailthe structural interrelationship of the condenser 24. A conduit 26extends from an outlet port in the condenser 24 to the inlet side of afan 28 shown schematically in FIGURE 1.

A conduit 30 extends from the outlet side of the fan 28 to the inletport of a heater 32 shown schematically in FIGURE 1. .A conduit 34extends from the outlet portof the heater 32 to the outlet chute 16 onthe housing 12. The conduit 32 is in communication with the interior ofthe outlet chute 16 with a screen 36 disposed therebetween as shown inFIGURE 1. For purposes of illustration,- the conduit 34 is connected tothe outlet chute16 at thebottom of the chute 16. It will be appreciatedthat the conduit 34will-be connected to a topwall of the outlet chute 16when the means for conveying the elements to be cleaned comprises animperforate conveyor belt. Aco'nduit 38 extends from the condenser 24 toany convenient receptacle such as a rinse bath disposed within thehousing. 12.

The cleaning apparatus'ltl of the present invention is utilized in thefollowing manner:

The elements to be cleaned will enter the housing 12 of the cleaningapparatus 10 by way ofthe inlet chute 14. A means will conveytheelements to be cleaned through the various stages of the cleaningprocess to the outlet chute 16. During the cleaning process, a heatingmeans willcause solvent within the housing 12 to be vaporized.

The vaporized solvent will be prevented from escaping to the atmospherethrough the inlet chute 14 because the end of the inlet chute 14 isdisposed below the'level of the solvent 20.

The closed air recirculation system will control the amount of vaporizedsolvent-within thehousing 12 and prevent escape of the same through theoutlet chute 16 in the following manner. Thesuction of fan 28 causes amixture of vaporized solvent and air disposed within the upper portionofthe housing 12 and clingingto the elements being cleaned to be drawninto the condenser 24 by way of conduit 22. The condenser 24separates-the vaporized solvent and air into liquid-solvent and coolair. The cool air passes from the condenser 24 into the inlet side ofthe tie-n28 by way of the conduit 26. The cool air is forced bytthe fan28 to pass through the conduit 30' to the heater 32, through' theconduit 34, into the inlet chute 16. The cool' air is warmed by theheater 32 as it passes therethrough.

The screen 36 in theoutletchute16precludes thepossibihty of elementsbeing cleaned within the apparatuslt) from entering the conduit 34.Since the warm air is at a temperature higher than that of theatmosphere at the outlet end of the chute 16, thewarm air rises upthechute 16, thereby sealing the-chute 16 with a-warm air barrier.

Since the discharge end of the chute 16 is lower thanthe level of theinlet end of the chute 16, and since the warm air delivered to the chute16 is the same air which was sucked out of the housing 12 by the fan 28,a closed circuit air recirculation system has been provided.-

The condensate of liquid solvent formed in the con denser 24 is conveyedby conduit 30 to any convenient receptacle such as rinse bath within thehousing 12. Preferably, the end of the conduit 38 remote from thecondenser 24 should be positioned below the level of liquid within thereceptacle. In this manner, the vaporized solvent and air cannot bedrawn out the conduit 38.

The fan 28 need only have a delivery capacity which produces the waft ofair in the chute 16. The term waft of air is to be interpreted asmovement of air which is barely perceptible; The amount of air movementvaries with the size of the cleaning apparatus. In a cleaning apparatushaving a 60 gallon supply of solvent, the fan capacity need only beapproximately cubic feet per minute. The wait of air in the chute 16 istoo insignificant to aspirate atmospheric air in through the dischargeend of the chute 16. Further, the waft of air delivered to the chute 16has a drying effect on'the elements being cleaned. In actual use, I havefound that only twelve ouncesof solvent were lost from the 60 gallonsupplyof solvent after eight hoursof continuous use. In the absence ofthe closed air recirculation system of those proposed heretofore sinceit prevents depletion of the supply of solvents within the housing ofthe cleaning apparatus, prevents escape of vaporized solvent to theatmosphere in those circumstances where such escape of vaporized solventwould be objectionable,.and enables a cleaning apparatus to be acomponent of a continuous the present invention, the 60 gallon supply ofsolvent would have been depleted by an amount substantially greater thantwelve ounces.

It will be understood that the condenser 24, the fan 28, and the heater32 are only shown schematically outside of the housing 12 for' purposesof illustration. These elements may be mounted in other positionsrelative to the housing 12. Also, it will be understood thatconventiorial details such as wiring and so on for these elements havenot been shown in the drawing.

The closed air recirculation system described above enables the cleaningapparatus 10 to be more efiicient than cleaning process.

FIGURE 2 discloses an alternative embodiment of the present inventiondesignated generally as 10'. The

cleaning apparatus 10 is identical with the cleaning apparatus 10 exceptas will be'made clear hereinafter. Accordingly, like elements in theapparatus 10 and 10 are designated with primed numerals. Accordingly, itis deemed necessary to further explain the structure and significance ofthose elements which arecommon to the cleaning apparatus 10 and 10'.

The cleaning apparatus 10' differs-from thecleaning apparatus 18 by theprovision of a horizontally disposed inlet passageway 44 and ahorizontally disposed outlet passageway 46. The inletand outletpassageways 44 and 46 need not be aligned with each other. A heater 48is provided having a pair of outlet ports. connected to one of theoutlet ports in the heater 48. The endof the conduit 50 remote from theheater 48 is connected to the outlet passageway 46 with a screen 52disposed therebetween.

A- conduit 54 is connected to the other outlet port of the heater 48.The end of the conduit 54 remote from the heater 48 is connectedto theinlet passageway 44 with a screen 56 disposed therebetween.

and 46 respectively.

The apparatus 10' of the present invention operates in the same manneras the apparatus 10. However, the

inlet'and outlet passageways 44 and 46 are'horizontally' disposed.Accordingly, the barrier of warm air which is provided in the inlet andoutlet passageways and 46 are prevented from escaping to the atmospheresurrounding the housing 12' because of the slightly negative pressureinduced in the housing 12' by the fan28. Aecordingly, it is notnecessary for the outlet passageway to be angled as shown in FIGURE 1,nor is it necessary for the end of the inlet passageway to be immersedbelow the level of a liquefied solvent. Since the air delivered to theinlet passageway 44 is warmer than the atmospheric air, there is aslight preheating of the elements to be cleaned within the housing 12'.In like mannenthe warm air delivered to the outlet passageway 46provides a slight drying efiect on the cleaned elements.

In certain special installations, it may be desirable to provide thecleaning apparatus with a combined inlet and' outlet passageway. Itwillbe appreciated bythoseskilled in the-art that the closed airrecirculation system of the present invention is equally adaptable foruse with such apparatus. I

It will be appreciated bythose skilledin the art that the presentinvention may be used in apparatus other than cleaning apparatus. Forexample, the present invention may be used in a painting apparatus orthe like wherein a flammable, toxic or costly thinner is being used.

A conduit 50 is Such use of the present invention is within the scope ofthe claims.

The present invention may be embodied in other specific forms withoutdeparting from the spirit or essential attributes thereof and,accordingly, reference should be made to the appended claims, ratherthan to the foregoing specification as indicating the scope of theinvention.

I claim:

1. In a cleaning apparatus comprising a housing, a wall of said housinghaving an inlet for receiving elements to be cleaned providingcommunication into said housing, a wall of said housing having an outletthrough which cleaned elements will emerge from said housing, mean-swithin said housing for defining a receptacle, said receptacle beingadapted to contain a cleaning solvent susceptible to being vaporizedduring the cleaning operation, and a means providing for a closedcircuit air recirculation system for said housing connected at its inletend to the housing and connected at its discharge end with said outletfor said housing in a manner so that the pressure within said housing ismaintained slightly below atmospheric pressure, said means including afan adapted to provide a waft of air to said outlet for said housing.

2. In a cleaning apparatus in accordance with claim 1 wherein said meansincludes apparatus for withdrawing a mixture of air and vaporizedsolvent from within said housing and feeding said withdrawn air backinto said discharge end of said housing in a warm state substantiallyfree from vaporized solvent.

3. In an apparatus in accordance with claim 2 includ ing a condenserdisposed between said housing and said fan, said fan being incommunication with said housing through said condenser, a heater incommunication with the outlet port of said fan, a conduit connecting theoutlet port of said heater with a portion of the outlet for saidhousing, and said condenser having a return conduit connected theretofor conveying liquid condensate away from said condenser to a suitablereceptacle.

4. In a cleaning apparatus comprising a housing, a wall of said housinghaving an inlet providing communication into said housing for receivingelements to be cleaned, a wall of said housing having an outlet throughwhich cleaned elements will emerge from said housing, means within saidhousing for defining a receptacle adapted to contain a cleaning solventsusceptible to being vaporized during the cleaning operation, meansproviding for a closer circuit air recirculation system for saidhousing, said last-mentioned means including apparatus for withdrawing amixture of air and vaporized solvent from within said housing andfeeding said withdrawn air back into said housing in a warm statesubstantially free from vaporized solvent, said Withdrawing meansincluding a fan, a condenser disposed between said housing and said fan,said fan being in communication with said housing through saidcondenser, a heater in communication with the outlet port of said fan, aconduit connecting the outlet port of said heater with a portion of theoutlet for said housing, said fan having a capacity for delivering onlya waft of air to said outlet of said housing, and said condenser havinga return conduit connected thereto for conveying liquid condensate awayfrom said condenser to a suitable receptacle, and a second conduitconnected to a second outlet port on said heater, said second conduitbeing connected to a portion of said inlet for said housing.

5. In a cleaning apparatus comprising a housing, a wall of said housinghaving an inlet for receiving elements to be cleaned providingcommunication into said housing, a wall of said housing having an outletthrough which cleaned elements will emerge from said housing, meanswithin said housing for defining a receptacle, said receptacle beingadapted to contain a cleaning solvent, said solvent being susceptible tobeing vaporized during the cleaning operation, and a means providing fora closed circuit air recirculation system for said housing in a mannerso that pressure within said housing is maintained slightly belowatmospheric pressure, said means providing for a closed circuit airrecirculation system including a conduit for delivering warm air freefrom vaporized solvent to each of said inlet and outlet, and said lastmentioned means also including a conduit connected to an intermediateportion of said housing between said inlet and outlet for withdrawing amixture of air and vaporized solvent.

6. In a cleaning apparatus comprising a housing having an inlet forreceiving elements to be cleaned and an outlet through which cleanedelements will emerge from said housing, means within said housing fordefining a receptacle adapted to contain a vaporizable solvent, meansfor withdrawing a mixture of air and vaporized solvent from said housingat a point between said inlet and outlet, said last mentioned meansincluding a condenser for separating the mixture into air and a liquid,means connected to the outlet side of said condenser for heating saidair and returning the same to each of said inlet and outlet.

References Cited in the file of this patent UNITED STATES PATENTS Re.17,594 Vance Feb. 11, 1930 1,947,174 Sando Feb. 13, 1934 2,011,083 SandoAug. 13, 1935 2,443,443 Chavannes June 15, 1948 2,896,640 Randall July28, 1959

1. IN A CLEANING APPARATUS COMPRISING A HOUSING, A WALL OF SAID HOUSINGHAVING AN INLET FOR RECEIVING ELEMENTS TO BE CLEANED PROVIDINGCOMMUNICATION INTO SAID HOUSING, A WALL OF SAID HOUSING HAVING AN OUTLETTHROUGH WHICH CLEANED ELEMENTS WILL EMERGE FROM SAID HOUSING, MEANSWITHIN SAID HOUSING FOR DEFINING A RECEPTACLE, SAID RECEPTACLE BEINGADAPTED TO CONTAIN A CLEANING SOLVENT SUSCEPTIBLE TO BEING VAPORIZEDDURING THE CLEANING OPERATION, AND A MEANS PROVIDING FOR A CLOSEDCIRCUIT AIR RECIRCULATION SYSTEM FOR SAID HOUSING CONNECTED AT ITS INLETEND TO THE HOUSING AND CONNECTED AT ITS DISCHARGE END WITH SAID OUTLETFOR SAID HOUSING IN A MANNER SO THAT THE PRESSURE WITHIN SAID HOUSING ISMAINTAINED SLIGHTLY BELOW ATMOSPHERIC PRESSURE, SAID MEANS INCLUDING AFAN ADAPTED TO PROVIDE A WAFT OF AIR TO SAID OUTLET FOR SAID HOUSING.